A communication system is used to communicate data between communication stations of the communication system. At least one communication station of the communication system forms a sending station that operates to send data. And, at least another of the communication stations forms a receiving station that operates to receive the data sent by a sending station. The data is communicated by the sending station upon a communication channel that extends between the sending and receiving stations. If necessary, the sending station converts the data into a form to permit its communication upon the communication channel. And, the receiving station operates to recover the informational content of the data based upon the data detected at the receiving station.
Many different types of communication systems have been developed and deployed, available for use to effectuate different types of communication services. As advancements in communication technologies permit, implementation of the advancements into existing, as well as new types of, communication systems shall likely permit improved and new communication services to be effectuated.
A radio communication system is an exemplary type of communication system. A radio communication system utilizes radio channels extending between sending and receiving stations and by way of which data is communicated therebetween.
Conventional wireline communication systems, in contrast, require the use of fixed, i.e., wireline connections extending between the sending and receiving stations, upon which to define communication channels. Because radio channels do not require the use of a wireline connection extending between the sending and receiving stations, a radio communication system can be utilized by way of which to effectuate communications when corresponding use of a wireline communication system is not possible. That is to say, free of the need to interconnect the communication stations by way of the wireline connections, communication stations of a radio communication system are positionable at locations between which wireline connections would not be feasible. Additionally, free of the need to interconnect the communication stations by way of wireline connections, a radio communication system is implementable as a mobile communication system in which one or more of the communication stations is permitted mobility.
A cellular communication system is a type of radio communication system. Cellular communication systems include network infrastructures, or networks, that are installed throughout geographical areas that are to be encompassed by the cellular communication system. Significant portions of the populated parts of the world are encompassed by the networks of cellular communication systems, constructed pursuant to various operational specifications, thereby to provide for cellular communication service throughout such populated areas of the world.
The network infrastructure of a cellular communication system includes fixed-site transceivers, sometimes referred to as base transceiver stations, each of which defines a coverage area, sometimes referred to as a cell. Sometimes fixed-site transceivers are constructed or otherwise deployed to provide communication coverage over limited areas, sometimes referred to as microcells. Communications are effectuated between a base transceiver station and a mobile station, or mobile node, when the mobile station is positioned within a coverage area encompassed by a base transceiver station. Other radio communication systems are analogously operable, also constructed to provide for radio communications with mobile stations when the mobile stations are positioned within areas encompassed by network infrastructures of the radio communication system. A wireless local area network (WLAN) is such a radio communication system that exhibits operational characteristics analogous to certain of the characteristics of a cellular communication system. More particularly, the network part of a wireless local area network includes fixed-site transceivers, sometimes referred to as access points, each of which defines a coverage area. A mobile station operable in the wireless local area network is generally capable of communicating with the access point in whose coverage area that the mobile station is positioned.
Cellular communication systems, wireless local area networks, as well as other radio communication systems, are sometimes constructed to utilize digital communication techniques. The use of digital communication techniques provides various communication advantages including, for instance, the capability of communicating data more efficiently. Communication conditions on radio channels by way of which data is communicated during operation of a cellular communication system, a WLAN, or other radio communication system, is generally non-ideal. For instance, fading conditions on the radio channel upon upon which the data is communicated distorts the values of the data. If the fading conditions are significant, and the effects of the fading are not compensated at the receiving station, the informational content of the data cannot correctly be recovered at the receiving station.
Channel equalizers are utilized at receiving stations to compensate for the effects of fading of data communicated upon a channel susceptible to fading. Channel equalizers perform their operations through use of channel estimations in which the communication conditions on the channels are estimated, generally in terms of a channel impulse response.
The performance of the equalizer is dependent, in part, upon the resolution of the channel estimate. Existing cellular communication systems and wireless local area networks are constrained in the resolution of the channel estimate that can be obtained. Generally, the channel estimate is derived by analyzing, or otherwise operating upon, a known sequence of values that are communicated to a communication station by way of a communication channel susceptible to fading. The correlation, or other comparison, of the received sequence of values with the known sequence, free of distortion, is used to estimate the channel. The constraints in the resolution capability is dependent, in part, upon the allocation of system capacity to communicate the sequence of the known values. Increase in the size of the known sequence is limited as such increase decreases the capacity of the system to communicate other data.
The use of ultrawide band (UWB) signaling has been proposed in other types of radio communication systems, such as in commercial television broadcasting. An ultrawide band signal is of large bandwidth, but of low power levels. If ultrawide band signals could be used in a cellular communication system, a wireless local area network, or other radio communication system for channel estimation purposes, improved estimation resolution could be provided. Additional advantages could also be provided through use of ultrawide band signaling in such systems.
It is in light of this background information related to radio communication systems that the significant improvements of the present invention have evolved.